In the surgical removal of gallstones it is necessary to make a very large incision, which often heals badly and forms large scars. As a result of the high recurrence rate of gallstone formation, it is in many cases necessary to surgically remove the entire gall bladder to avoid the repeated removal of such stones. Quite apart from the fact that such an operation is very unpleasant and requires a long stay in the hospital, it is subject to high risks. It must be carried out under general anesthetic, which always forms a significant risk. It is also impossible to crush and remove by ultrasonic litholapaxy soft stones, such as cholesterin and pigment stones. Attempts have also been made to destroy gallstones by laser beams, but this is not of an optimum nature for all stone types.
Attempts have been made to remove deposits in blood vessels by a knife rotating in a catheter provided with a lateral window. However, satisfactory results have not been obtained.
Normally thrombi are gripped by an atherectomy loop or sling, are crushed as far as possible and drawn out through a guiding catheter and this can be assisted by suction. This process is complicated and requires considerable sensitivity on the part of the surgeon. A separated thrombus part can easily slide out of the loop, be carried on and clog narrower vessels.
Furtheron deposits, such as thrombotic occlusions in vessels or the like may be removed by a rotary element moved in the vessel towards the closing or constriction and with respect to which a rotational speed of about 100,000 r.p.m. has been proposed in order to pulverize the occlusion material. However, there is a risk of the pulverized particles being redeposited at other points and possibly in much narrower, but important vessels, where damage can be caused. Other apparatuses rotating at a lower speed up to max 500 r.p.m. merely move the vessel-closing material to the side. Thus, it is not possible to achieve a reliable, permanent exposure of a stenosis, quite apart from an opening of an occlusion. In addition, apparatuses are known, which cut out constricting material in the vessel in one way or another. To the extent that a rotary catheter is used, the danger exists that it takes the vessel wall with it during its rotation with the associated risk of an entanglement, so that here again it is only possible to operate at very low speeds. To the extent that the removal takes place by working instruments passed through a catheter on a shaft, then the instruments must operate at a distance from the catheter orifice, so that possibly the suction exerted by the catheter will not be adequate for removing all the abraded particles.